AprilAire E100 Review: Big Capacity, If You Plan the Ducts

The AprilAire E100 is the whole-house dehumidifier we'd buy for a humid house with ductwork to tie into, or for a big sealed crawl space or basement that stays above the mid-50s. ENERGY STAR certifies it at 85 pints/day under the current DOE whole-home test (73°F, 60% RH) and lists it as Most Efficient. It moves 280 CFM, ducts with 10 in collars, and plugs into an ordinary outlet.

What it won't do is dry a whole house from a corner of the basement. Set up as a standalone box, it dries the room it sits in and not much else. It quits below 50°F inlet air, so it isn't the unit for a crawl space that runs cold all winter. And the 5,500 sq ft on the box is a marketing range, not a promise: in humid Southern houses, owners report it running around the clock and still missing its setpoint. Plan the ductwork, the drain and the controls before you order, and it's an excellent machine.

Where the E100 earns its price

• Certified capacity: 85 pints/day at the 73°F whole-home test, the number to size by, and 100 at the older 80°F rating.
• Efficiency: an integrated energy factor of 2.35 L/kWh and ENERGY STAR Most Efficient status.
• Air to work with: 280 CFM with no ductwork attached and 175 CFM at 0.6 in. of static pressure, its stated limit, so it can push dry air through real duct runs.
• Support: owners describe AprilAire diagnosing problems by phone and quickly shipping a fan assembly or a whole replacement unit.

Where it falls short

• Cold spaces: no dehumidifying below 50°F inlet air or a 40°F dew point.
• No pump: you need a floor drain, a gravity path or a separate condensate pump.
• Remote locations: in a crawl space or attic you'll want the Model 76 remote control, an extra purchase.
• Noise in the ducts: AprilAire's 2021 spec sheet lists 55 dBA ducted, and one owner hears it at every connected vent.
• Sizing claims: the coverage figure assumes a lot; a leaky, humid house can outrun it.

E100, E100W, E100C and the other letters

AprilAire sells the same 100-pint box in several versions, and Amazon adds bundle names of its own. Here's how they line up.

For most buyers the choice is between the plain E100 and the E100W bundle. The W adds app control, which matters when the unit lives under the house, and the Amazon bundle adds the pump and hanging kit the plain E100 leaves you to buy.

The ratings, and the test behind each one

AprilAire's manual rates the E100 at 100 pints/day at 80°F and 60% RH, the old AHAM condition. Since June 2019 the DOE has rated whole-home dehumidifiers at 73°F and 60% RH, and ENERGY STAR lists the E100 at 85 pints/day under that test. Size by the 85. Cooler air holds less water, so the same machine removes about 85% as much at 73°F as at 80°F, and less again in a 60°F basement or crawl space.

A few comparisons are fair from that table and a few aren't. At 80°F, the one condition AprilAire prints for all three, the E100 is rated 43% above the E070 and 25% above the E080. At 73°F it's 31% above the E080 and 62% above Santa Fe's ducted Ultra70. The Compact70's 43.7 comes from the 65°F portable test, so don't hold it against the E100's 85; at equal conditions the gap would likely be smaller, and nobody publishes that comparison.

On energy, 85 pints is about 40 liters of water. At 2.35 L/kWh that's roughly 17 kWh to remove a full day of rated capacity, and the unit draws about 770 W while it runs (6.7 A at 115 V). ENERGY STAR estimates 821 kWh a year. It cycles off when it reaches the setpoint, so most houses use less than the full-day figure on most days.

The rest of the sheet: the cabinet is 14 in wide, 15 in high and 26 in long, plus duct collars, and weighs 64 lb. The filter is a washable MERV 8. AprilAire's 2021 spec sheet lists 55 dBA ducted; the current manual and shop pages give no noise figure.

Ducted, standalone or under the house

How you install the E100 decides what it dries. Set it in the basement on its own and it dries the basement. Duct it into the HVAC system and it can dry the house. AprilAire's own spec sheet lays out four ductwork setups, and the one it recommends pulls air from the main return and sends it back into the return. Ducted, it does noticeably more for the rest of the house; left standalone in a finished basement, it can leave the basement dry and the floors above near 60%.

• Ducting limits: the manual says the duct system the E100 works against must not exceed 0.6 in. w.c., measured with the furnace fan on its highest setting. It also notes some local codes don't allow ducting to the return side. Use insulated duct anywhere it runs through unconditioned space.
• Drain: it drains through a 3/4 in fitting by gravity with a constant downward slope. There's no pump in the cabinet; AprilAire's Model 4856 pump lifts 22 ft.
• Above finished space: the manual requires a condensate pan under the unit, with a float switch or the pump's overflow contacts set to stop the dehumidifier if water backs up.
• Hard-to-reach spots: for a crawl space, attic or out-of-the-way basement, the manual suggests the Model 76 control mounted in the living space. In a hot attic, the E100's own sensor reads the attic air and can overshoot and undershoot; the Model 76 fixes that.
• Electrical: the E100 and E100W plug into a standard 115 V grounded outlet. The E100H is hardwired, and the manual says electrical servicing belongs to a qualified, licensed electrician; that includes adding an outlet in a crawl space.

If the E100 sits below the nearest drain, a separate pump such as the Little Giant VCMA-15 does the lifting. Wiring the E100 to a thermostat or the furnace is low-voltage work the manual documents; if that's beyond you, run it on its own control or the Model 76 and leave the furnace alone.

A crawl space install goes faster than a ducted one. One owner with a crawl space wrapped around a walkout basement had it running the day it arrived and saw humidity fall from 69-70% to 45% in about three days, without a crawl space company. The catch in a crawl space is temperature: if the space drops below 50°F in winter, the E100 sits idle until spring. If yours runs colder than that, the AlorAir Sentinel HD55S is rated to keep working down to 33.8°F.

What owners report

Owner reports split along one line. In moderate houses with the unit ducted or placed where the moisture is, owners are happy, and the clearest results come from crawl spaces and ducted installs. In humid Southern and border-state houses, owners report the E100 running nonstop without reaching its setpoint, and some call its capacity oversold. We'd read most of that as sizing and installation rather than defects. The 5,500 sq ft claim says nothing about how leaky or humid a house is, and an air conditioner with its fan set high or left running puts moisture back into the air that the dehumidifier just removed.

Some underperforming units are defective, though, and AprilAire handles that well. An Alabama owner's E100 pulled plenty of water at first, then trickled for two months while running nonstop. AprilAire walked them through an air sample test over the phone, judged the unit faulty and shipped a replacement within days of proof that the old one was disabled; the new one worked much better. A fan that started making a high-pitched, cricket-like noise got the same treatment: a five-minute call, a receipt, and a new fan assembly in the mail. If yours runs all day and the drain line stays nearly dry, call AprilAire before you blame your house.

Noise comes up too. Ducted into the system, the E100 can be heard at the registers of a quiet house, and AprilAire's manual recommends suspending it in an attic to reduce noise transfer. Hang it on isolators or set it on a pad wherever it's near living space.

Warranty and where to buy

The E100 manual gives five years from the date of purchase against defects in materials or workmanship. AprilAire chooses whether to replace a part or the whole product. Labor, shipping, removal, service and reinstallation costs aren't covered, and neither are used units bought from third parties. The warranty is void if a defect results from not installing the unit according to AprilAire's instructions, which makes the ducting, pan and drain rules above worth following to the letter.

The E100W is sold with a longer promise. Its shop page advertises a 6-year warranty, five years of full replacement plus one year of parts, but the Amazon E100W bundle's warranty field says five years and we couldn't locate a printed E100W warranty. Save a copy of the shop page with your receipt. Buy new, from Amazon itself or a dealer, so the used-unit exclusion never comes up.

How it compares

• AprilAire E070: the same design in a smaller box: 70 pints/day at 80°F, 200 CFM and 8 in collars. Buy it for a typical crawl space; buy the E100 when you're ducting into a whole house or the space is large and wet.
• AprilAire E080: 65 pints/day at 73°F and 185 CFM, with a lower 0.4 in. static limit. It cost less than the E100 when we checked, but the E100's 31% more capacity at the same test is worth paying for in a ducted install.
• Santa Fe Ultra70: Santa Fe's ducted whole-home unit at 52.45 pints/day at 73°F, 150 CFM and 8 in ducts. The E100 publishes 62% more at the same condition.
• Santa Fe Compact70: the better crawl space unit when you want a MERV-13 filter and a published 65°F rating; it rates down to 49°F inlet air, a degree below the E100.
• AlorAir Sentinel HD55S: a fraction of the price and rated to run at 33.8°F, so it's the pick for a crawl space that gets cold. It's rated 36.33 pints/day at 65°F and doesn't duct like the E100.

Our call on the E100

Buy the E100 if you're ducting a dehumidifier into a forced-air house, or drying a large sealed crawl space or basement that stays above the mid-50s. Get the E100W bundle if the unit will live somewhere you won't visit, so you can check it from your phone and the pump comes in the box. Size it by the 85 pints at 73°F, not the coverage claim, and give it a few weeks: if it runs constantly with a dry drain line, call AprilAire while you're inside the five years.

Skip it if your crawl space drops below 50°F in winter, if you're hoping one standalone unit in the basement will dry the upstairs, or if the problem is an air conditioner moving too much air. Fix the fan speed first. A dehumidifier this size is the answer for a house that stays damp after that.